Intensity Imaging Research Articles

Observing bioorthogonal macrocyclizations in the nuclear envelope of live cells using on/on fluorescence lifetime microscopy.

The reactive partnership between azides and strained alkynes is at the forefront of bioorthogonal reactions, with their in situ cellular studies often achieved through the use of off to on fluorophores with fluorescence microscopy. In this work, the first demonstration of a bioorthogonal, macrocycle-forming reaction occurring within the nuclear envelope of live cells has been accomplished, utilising on/on fluorescence lifetime imaging microscopy for real-time continuous observation of the transformation. The fluorescent, macrocyclic BF2 azadipyrromethene was accessible through a double 1,3-dipolar cycloaddition within minutes, between a precursor bis-azido substituted fluorophore and Sondheimer diyne in water or organic solvents. Photophysical properties of both the starting bis-azide BF2 azadipyrromethene and the fluorescent macrocyclic products were obtained, with near identical emission wavelengths and intensities, but different lifetimes. In a novel approach, the progress of the live-cell bioorthogonal macrocyclization was successfully tracked through a fluorescence lifetime change of 0.6 ns from starting material to products, with reaction completion achieved within 45 min. The continuous monitoring and imaging of this bioorthogonal transformation in the nuclear membrane and invaginations, of two different cancer cell lines, has been demonstrated using a combination of fluorescence intensity and lifetime imaging with phasor plot analysis. As there is a discernible difference in fluorescence lifetimes between starting material and products, this approach removes the necessity for off-to-on fluorogenic probes when preparing for bioorthogonal cell-imaging and microscopy.

Bayesian Statistical Analysis for Bacterial Detection in Pulmonary Endomicroscopic Fluorescence Lifetime Imaging.

Pneumonia, a respiratory disease often caused by bacterial infection in the distal lung, requires rapid and accurate identification, especially in settings such as critical care. Initiating or de-escalating antimicrobials should ideally be guided by the quantification of pathogenic bacteria for effective treatment. Optical endomicroscopy is an emerging technology with the potential to expedite bacterial detection in the distal lung by enabling in vivo and in situ optical tissue characterisation. With advancements in detector technology, optical endomicroscopy can utilize fluorescence lifetime imaging (FLIM) to help detect events that were previously challenging or impossible to identify using fluorescence intensity imaging. In this paper, we propose an iterative Bayesian approach for bacterial detection in FLIM. We model the FLIM image as a linear combination of background intensity, Gaussian noise, and additive outliers (labelled bacteria). While previous bacteria detection methods model anomalous pixels as bacteria, here the FLIM outliers are modelled as circularly symmetric Gaussian-shaped objects, based on their discrete shape observed through visual analysis and the physical nature of the imaging modality. A Hierarchical Bayesian model is used to solve the bacterial detection problem where prior distributions are assigned to unknown parameters. A Metropolis-Hastings within Gibbs sampler draws samples from the posterior distribution. The proposed method's detection performance is initially measured using synthetic images, and shows significant improvement over existing approaches. Further analysis is conducted on real optical endomicroscopy FLIM images annotated by trained personnel. The experiments show the proposed approach outperforms existing methods by a margin of +16.85% ( F1 ) for detection accuracy.

Optically induced fabrication of three-dimensional photonic lattice microstructures by using cutting-combination lens

A convenient method for producing three-dimensional photonic lattice microstructures was experimentally demonstrated by using a cutting-combination lens. Three-dimensional photonic lattices are optically induced by (4 + 1) plane waves interference in an iron-doped lithium niobate photorefractive crystal. Induced three-dimensional lattice microstructures are observed and verified by planar guided wave intensity imaging and far-field diffraction pattern. This method is inexpensive and does not require complex adjustment devices. In addition, it also has flexibility and scalability. This method can be used to fabricate other more complex three-dimensional photonic lattice microstructures by designing the cutting-combination lens appropriately.

Tunable Far‐Infrared Polarization Imaging Based on VO2 Metasurfaces

AbstractPolarization imaging enables the capture of material properties and surface characteristics of objects, finding applications in remote sensing and defense. However, most existing polarization imaging systems rely on polarization filtering elements, resulting in energy loss exceeding 50% and compromising intensity imaging performance. Conventionally, a rotary device equipped with different polarizers and a blank area is used to acquire both polarization and intensity images, which is cumbersome for integration and miniaturization purposes. In this study, a miniaturized and easily integrated active metasurface based on VO2 grating structure for switchable detection of intensity and polarization in the far‐infrared band (8–14 µm) is proposed. With VO2 in the dielectric state, the device exhibits high transmittance for both TE‐ and TM‐polarized light (Experimental transmittance of up to 65%). Upon phase transition to the metallic state, the device demonstrates low transmittance for TE‐polarized light while maintaining high transmittance for TM‐polarized light (linear polarization extinction ratio up to 10 dB). Finally, the tunable thermal intensity and polarization imaging capabilities of the custom‐made setup are characterized. The metasurface showcases comparable performance to standard commercial polarizers in terms of polarization imaging. The developed tunable far‐infrared polarization imaging system holds promise for next‐generation multidimensional information perception.

Vehicle Headlight Halo Simulation of Presbyopia-Correcting Intraocular Lenses.

This optical bench study was designed to evaluate and compare the halos generated by presbyopia-correcting intraocular lenses (PCIOLs) and monofocal intraocular lenses (IOLs), with or without lens decentration, using an optical bench to simulate the headlight of a distant vehicle in mesopic conditions. Halos generated by six nondiffractive and 10 diffractive IOLs with different dioptric add powers were evaluated using a high dynamic range bench system. Halo intensities were compared by assessing the area under the measured intensity profile curve to compute the relative halo magnitude (RHM). Nondiffractive PCIOLs produced smaller and less intense bench halo images than diffractive ones. RHM measurements ranged from 964 to 1896. Monofocal IOLs produced lower RHM values, whereas diffractive PCIOLs generated higher ones. When decentered by 0.5 mm with respect to the system aperture, more obviously asymmetric halo image profiles were observed in diffractive compared with nondiffractive PCIOLs. Simulated bench halos of nondiffractive PCIOLs are smaller and less intense than those of diffractive PCIOLs. Additional clinical studies assessing standardized patient-reported outcomes measures are required to correlate these bench results with patient satisfaction. This study contrasts the design-related simulated bench halos of nondiffractive and diffractive PCIOLs, aiming to elucidate their impact on halo perception.

Julian of Norwich’s a Revelation of Love: A Grounded Cognition Approach to a Late Medieval Text

Julian of Norwich was a late medieval anchoress and writer, whose work, The Showings, is known for its vivid imagery and bodily resonance it prompts in the reader. The paper identifies a gap in research on the embodied aspects of Julian’s imagery. The article discusses the connection between perception, action and the grounded nature of cognition, exploring its role in structuring Julian’s text. It uses the conceptions of situated conceptualisation and sociocultural situatedness to embed the work in the visual/material culture of the Middle Ages. It reveals how the mystic construes emotionally intense images, which underpin the abstract language of the text’s final chapters. To conclude, the recent conceptions from cognitive science may expand the analytical toolkit of cognitive-diachronic research in particular, helping illuminate the interplay of language, culture, and cognition.

Development of a semi-automatic segmentation technique based on mean magnetic resonance imaging intensity thresholding for volumetric quantification of plexiform neurofibromas

Rationale and objectivesPlexiform neurofibromas (PNs) are peripheral nerve tumors that occur in 25–50 % of patients with neurofibromatosis type 1. PNs may have complex, diffused, and irregular shapes. The objective of this work was to develop a volumetric quantification method for PNs as clinical assessment is currently based on unidimensional measurement. Materials and methodsA semi-automatic segmentation technique based on mean magnetic resonance imaging (MRI) intensity thresholding (SSTMean) was developed and compared to a similar and previously published technique based on minimum image intensity thresholding (SSTMini). The performance (volume and computation time) of the two techniques was compared to manual tracings of 15 tumors of different locations, shapes, and sizes. Performance was also assessed using different MRI sequences. Reproducibility was assessed by inter-observer analysis. ResultsWhen compared to manual tracing, quantification performed with SSTMean was not significantly different (mean difference: 1.2 %), while volumes computed by SSTMini were significantly different (p < .0001, mean difference: 13.4 %). Volumes quantified by SSTMean were also significantly different than the ones assessed by SSTMini (p < .0001). Using SSTMean, volumes quantified with short TI inversion recovery, T1-, and T2-weighted imaging were not significantly different. Computation times used by SSTMean and SSTMini were significantly lower than for manual segmentation (p < .0001). The highest difference measured by two users was 8 cm3. ConclusionOur method showed accuracy compared to a current gold standard (manual tracing) and reproducibility between users. The refined segmentation threshold and the possibility to define multiple regions-of-interest to initiate segmentation may have contributed to its performance. The versatility and speed of our method may prove useful to better monitor volumetric changes in lesions of patients enrolled in clinical trials to assessing response to therapy.

Dual Aggregations of a Near-Infrared Aggregation-Induced Emission Luminogen for Enhanced Imaging of Alzheimer's Disease.

Aggregation-induced emission (AIE) enables "Turn-On" imaging generally through single aggregation of the AIE luminogen (AIEgen). Dual aggregrations of the AIEgen might further enhance the imaging intensity and the consequent sensitivity. Herein, we rationally designed a near-infrared (NIR) AIEgen Ac-Trp-Glu-His-Asp-Cys(StBu)-Pra(QMT)-CBT (QMT-CBT) which, upon caspase1 (Cas1) activation, underwent a CBT-Cys click reaction to form cyclic dimers QMT-Dimer (the first aggregation) and assembled into nanoparticles (the second aggregation), turning the AIE signal "on" for enhanced imaging of Alzheimer's disease (AD). Molecular dynamics simulations validated that the fluorogen QMT in QMT-NPs stacked much tighter with each other than in the single aggregates of the control compound Ac-Trp-Glu-His-Asp-Cys(tBu)-Pra(QMT)-CBT (QMT-CBT-Ctrl). Dual aggregations of QMT rendered 1.9-, 1.7-, and 1.4-fold enhanced fluorescence intensities of its single aggregation in vitro, in cells, and in a living AD mouse model, respectively. We anticipate this smart fluorogen to be used for sensitive diagnosis of AD in the clinic in the near future.

Tabletop extreme ultraviolet reflectometer for quantitative nanoscale reflectometry, scatterometry, and imaging.

Imaging using coherent extreme-ultraviolet (EUV) light provides exceptional capabilities for the characterization of the composition and geometry of nanostructures by probing with high spatial resolution and elemental specificity. We present a multi-modal tabletop EUV imaging reflectometer for high-fidelity metrology of nanostructures. The reflectometer is capable of measurements in three distinct modes: intensity reflectometry, scatterometry, and imaging reflectometry, where each mode addresses different nanostructure characterization challenges. We demonstrate the system's unique ability to quantitatively and non-destructively measure the geometry and composition of nanostructures with tens of square microns field of view and sub-nanometer precision. Parameters such as surface and line edge roughness, density, nanostructure linewidth, and profile, as well as depth-resolved composition, can be quantitatively determined. The results highlight the applicability of EUV metrology to address a wide range of semiconductor and materials science challenges.

Age-stratified risk factors of re-intervention for uterine fibroids treated with high-intensity focused ultrasound.

To estimate the rate and risk factors of re-intervention for patients with uterine fibroids (UFs) undergoing high-intensity focused ultrasound (HIFU) at different age distributions. A retrospective cohort study was conducted in Nanchong Central Hospital, recruiting a total of 672 patients with UFs undergoing HIFU from June 2017 to December 2019. Using univariate and multivariate logistic regression, risk factors for re-intervention were assessed. Among 401 patients with UFs who completed the follow-up visits (median 47 months, range 34-61), 50 (12.46%) patients underwent re-intervention (such as high-intensity focused ultrasound, uterine artery embolization, myomectomy and hysterectomy). In the different age distributions, the re-intervention rate was 17.5% (34/194) in patients aged <45 years and 7.7% (16/207) in those aged ≥45 years. Regarding the younger patient group (aged <45 years), hypo- or iso-intensive fibroids in T2-weighted magnetic resonance imaging (T2WI) intensity may elevate the risk of re-intervention for UFs (odds ratio [OR] 2.96, 95% confidence interval [CI] 1.37-6.62; P = 0.007). Among the older patient group (aged ≥45 years), preoperative anemic patients had an increased risk of re-intervention compared with those without anemia (OR 3.30, 95% CI 1.01-10.37; P = 0.041). The re-intervention rate of HIFU decreased with increasing age. Among those aged <45 years, T2WI intensity was the independent risk factor for re-intervention, and among those aged ≥45 years, preoperative anemic status may be related to re-intervention outcome.

Ultrasound in sports traumatology.

Ultrasound (US) has numerous applications in sports traumatology. The technical progress of mobile US devices has led to increasing use of ultrasound as a primary diagnostic tool. New applications such as elastography and 3 D vascularization are used for special indications. The purpose of this review is to present the current status of ultrasound in the diagnosis of sports injuries and sport traumatology including established applications and new technical advances. US is presented both in its comparison to other imaging modalities and as a sole diagnostic tool. US can be used for initial diagnosis to improve the clinical examination and for intensive short-term follow-up imaging. The main areas of application are currently the diagnosis of acute muscle and tendon injuries as well as overuse injuries. In particular, the exclusion of structural muscle injuries can be adequately ensured with US in the majority of anatomical regions. The recently published guideline on fracture ultrasound has strengthened the clinical evidence in this area, especially in comparison to conventional radiography and in the development of algorithms and standards. The increasing use of mobile ultrasound equipment with adequate image quality makes US a location-independent modality that can also be used at training sites or during road games. · Typically used for quick, focused initial diagnostic assessment and short-term follow-up after injury. · Mobile US devices allow increased use in training centers and training camps. · New US applications (SWE, 3 D) increase standardization in follow-up of tendon injuries. · Targeted use of US for musculoskeletal diagnostic assessment saves money and frees up capacity. · Lerchbaumer MH, Perschk M, Gwinner C. Ultrasound in sports traumatology. Fortschr Röntgenstr 2024; 196: 440 - 449.

Management of congenital urogenital and perineal vascular malformations: correlation of clinical findings with diagnostic imaging for treatment decision.

Analysis of clinical and diagnostic findings in rare urogenital and perineal vascular malformations only occurring in 2-3 % of vascular anomalies with regard to clinical symptoms and treatment decisions. All 25 out of 537 patients presenting with congenital urogenital and perineal vascular malformations at our institution from 2014 to 2021 were included. Vascular anomaly classification, anatomical location, clinical symptoms at presentation, diagnostic imaging, and pain intensity were retrospectively assessed from the patient record and therapy management was evaluated. In total, 25 patients (10 females (40 %), 15 males (60 %)), aged 6 to 77 years were included. Diagnoses were: 10 (40 %) venous malformations (VMs), 5 (20 %) lymphatic malformations (LMs) and 10 (40 %) arteriovenous malformations (AVMs). Malformation manifestations were: 12 (32 %) lesser pelvis, 12 (32 %) external genitalia, and 13 (34 %) perineal/gluteal region. One AVM was located in the kidney. The leading clinical symptom was pain. The mean intensity was 6.0/10 for LM, 5.7/10 for VM, and 4.5/10 for AVM. Further major symptoms included physical impairment, local swelling, and skin discoloration. Bleeding complications or sexual dysfunction were rare findings. Patients with VM reported significantly more symptoms than patients with AVM (p = 0.0129). In 13 patients (52 %) minimally invasive therapy was indicated: 10 (77 %) sclerotherapies and 3 (23 %) transcatheter embolization procedures. Complete symptomatic remission was achieved in 9 (69 %) patients, partial response in 3 (23 %) patients, and 1 patient showed no clinical response to therapy. Follow-up appointments without the need for immediate minimally invasive therapy were significantly more common in patients with AVMs than in patients with VMs (p = 0.0198). To create a higher awareness of congenital urogenital and perineal vascular malformations. Awareness of this rare condition avoids misdiagnosis. Therapy decisions should be symptom-oriented. Emergency intervention is rarely required, even in fast-flow vascular malformations. · Venous malformations cause more symptoms with higher pain intensity than arteriovenous malformations.. · Diagnosis and adequate treatment can be hampered by a lack of awareness of the clinical presentation.. · Bleeding complications are rare, even in high-flow vascular malformations.. · Pain and physical impairment are the most commonly observed symptoms in these patients..

Nebular C iv λ1550 Imaging of the Metal-poor Starburst Mrk 71: Direct Evidence of Catastrophic Cooling

We use the Hubble Space Telescope Advanced Camera for Surveys to obtain the first spatially resolved, nebular imaging in the light of C iv λ λ1548, 1551 by using the F150LP and F165LP filters. These observations of the local starburst Mrk 71 in NGC 2366 show emission apparently originating within the interior cavity around the dominant super star cluster (SSC), Knot A. Together with imaging in He ii λ4686 and supporting Space Telescope Imaging Spectrograph far-ultraviolet spectroscopy, the morphology and intensity of the C iv nebular surface brightness and the C iv/He ii ratio map provide direct evidence that the mechanical feedback is likely dominated by catastrophic radiative cooling, which strongly disrupts adiabatic superbubble evolution. The implied extreme mass loading and low kinetic efficiency of the cluster wind are reasonably consistent with the wind energy budget, which is probably enhanced by radiation pressure. In contrast, the Knot B SSC lies within a well-defined superbubble with associated soft X-rays and He ii λ1640 emission, which are signatures of adiabatic, energy-driven feedback from a supernova-driven outflow. This system lacks clear evidence of C iv from the limb-brightened shell, as expected for this model, but the observations may not be deep enough to confirm its presence. We also detect a small C iv-emitting object that is likely an embedded compact H ii region. Its C iv emission may indicate the presence of very massive stars (>100 M ⊙) or strongly pressure-confined stellar feedback.

Abstract 154: Training Independent Artificial Intelligence Models for the Detection of Intracranial Pathology

Introduction Intracranial hemorrhage (ICH) and brain parenchymal midline shift (MLS) are medical emergencies and require timely diagnosis for early triage to lifesaving care. Artificial intelligence (AI) has shown potential in shortening the time to diagnosis. Although most of models have been compromised with the need of training sample resulting in overfitting as an obstacle to generalizability of models. In this study we introduce independent training models for the early detection of intracranial pathologies in imaging. Methods The software was developed using Python version 3.11.3. Software packages NumPy, scipy, skimage, stardist, and matpotlib were used for imaging intensity, color, and a shape‐based auto segmentation of intracranial objects. Results The current AI model is able to auto segment the Pineal gland for measurement of MLS (Figure‐1), and can detect imaging evidence of the hyperdense vessel sign (Figure‐2), and demonstrative large intracranial vessel (Figure‐3). Conclusion Our auto segmentation model is based on objects features instead of training models, thus providing a fast, generalizable, and feasible AI model. This tool has adjacent utility for detection and segmentation of intracranial vessels, hemorrhage, and midline shift.

TSMPN-PSI: high-performance polarization scattering imaging based on three-stage multi-pipeline networks.

Polarization imaging, which provides multidimensional information beyond traditional intensity imaging, has prominent advantages for complex imaging tasks, particularly in scattering environments. By introducing deep learning (DL) into computational imaging and sensing, polarization scattering imaging (PSI) has obtained impressive progresses, however, it remains a challenging but long-standing puzzle due to the fact that scattering medium can result in significant degradation of the object information. Herein, we explore the relationship between multiple polarization feature learning strategy and the PSI performances, and propose a new multi-polarization driven multi-pipeline (MPDMP) framework to extract rich hierarchical representations from multiple independent polarization feature maps. Based on the MPDMP framework, we introduce a well-designed three-stage multi-pipeline networks (TSMPN) architecture to achieve the PSI, named TSMPN-PSI. The proposed TSMPN-PSI comprises three stages: pre-processing polarization image for de-speckling, multiple polarization feature learning, and target information reconstruction. Furthermore, we establish a real-world polarization scattering imaging system under active light illumination to acquire a dataset of real-life scenarios for training the model. Both qualitative and quantitative experimental results show that the proposed TSMPN-PSI achieves higher generalization performance than other methods on three testing data sets refer to imaging distances, target structures, and target materials and their background materials. We believe that our work presents a new framework for the PSI and paves the way to its pragmatic applications.

Direct feature extraction and image co-registration of morphological structure from Bayer pattern raw planetary images

Feature extraction from planetary remote sensing images is a primary image processing task for object recognition, crater counter, morphological structure dimension and unpaired image co-registration. The paper presents a novel methodology to extract features directly from Bayer Pattern raw planetary images. Gradient information is extracted from Bayer Pattern image using standard edge operator that follows Color Difference Constancy (CDC) assumption. The proposed method's advantage is that it can skip the computationally intensive image processing pipeline and can have the Bayer Pattern raw planetary image flow directly for useful information extraction. Sobel Edge Detector is applied on Indian Mars Color Camera (MCC) Bayer Pattern raw images, and Gradient Magnitude Map (GMM) is generated at different Martian terrains. In addition, we have developed a direct image co-registration approach for MCC Bayer intensity raw image with respect to Mars Digital Image Model (MDIM) 2.1 reference using Mode-Mean Combo Patch Filler and Gradient Intensity induced Scale Invariant Feature Transform (GI-SIFT) based feature matching. The outlier matched points are removed by Feature Similarity Score guided Random Sample Consensus (FSS-RANSAC) estimation technique. The visual evaluation and quantitative metrics indicate that GMM from MCC Bayer Pattern raw image has negligible degradation with respect to GMM extracted from MCC demosaic image. The Root Mean Square Error (RMSE) is computed at different Mars regions, and it is found that the average image co-registration accuracy is less than 0.5 pixel.

Analysis of Two-Color Infrared Polarization Imaging Characteristics for Target Detection and Recognition

Infrared polarization imaging has demonstrated significant advantages in target detection and recognition in natural environments. While there have been numerous research achievements on medium-wave/long-wave infrared polarization in a single band, there is a lack of related conclusions on the characteristics of wide spectral two-color infrared polarization imaging. To address this gap, this article employs a theoretical model in infrared polarization imaging to investigate the influence of temperature, incident angle, and refractive index on polarization degree and polarization angle. These findings have been substantiated through discussions on experimental results. We conducted a comparative analysis between intensity imaging and polarization imaging within the framework of traditional single-band infrared imaging. We then delineated the benefits of dual-color infrared polarization imaging. Finally, we harnessed image registration fusion algorithms to amalgamate multiple-band images. Our findings demonstrate that this fusion technique not only enables penetration through water mist but also enhances target visibility, providing theoretical support for all-weather target detection and identification.

A Mitochondria-Localized Iridium(III) Complex for Simultaneous Two-Photon Phosphorescence Lifetime Imaging of Downstream Products N2O3 and ONOO- of Endogenous Nitric Oxide.

Nitric oxide (NO) serves as a ubiquitous and fundamental signaling molecule involved in intricate effects on both physiological and pathological processes. NO, biosynthesized by nitric oxide synthase (NOS) or generated from nitrite, can form nitrosation reagent N2O3 (4NO + O2 = 2N2O3) through its oxidation or quickly produce peroxynitrite anion ONOO- (NO + •O2- = ONOO-) by reacting with superoxide anion (•O2-). However, most of the existing luminescent probes for NO just focus on specificity and utilize only a single signal to distinguish products N2O3 or ONOO-. In most of the present work, they differentiate one product from another simply by fluorescence signal or fluorescence intensity, which is not enough to distinguish accurately the behavior of NO in living cells. Herein, a new mitochondria-targeted and two-photon near-infrared (NIR) phosphorescent iridium(III) complex, known as Ir-NBD, has been designed for accurate detection and simultaneous imaging of two downstream products of endogenous NO, i.e., N2O3 and ONOO-. Ir-NBD exhibits a rapid response to N2O3 and ONOO- in enhanced phosphorescence intensity, increased phosphorescence lifetime, and an exceptionally high two-photon cross-section, reaching values of 78 and 85 GM, respectively, after the reaction. Furthermore, we employed multiple imaging methods, phosphorescence intensity imaging, and phosphorescence lifetime imaging together to image even distinguish N2O3 and ONOO- by probe Ir-NBD. Thus, coupled with its excellent photometrics, Ir-NBD enabled the detection of the basal level of intracellular NO accurately by responding to N2O3 and ONOO- in the lipopolysaccharide-stimulated macrophage model in virtue of fluorescence signal and phosphorescence lifetime imaging, revealing precisely the endogenous mitochondrial NO distribution during inflammation in a cell environment.

Thickness Nanoarchitectonics with Edge-Enhanced Raman, Polarization Raman, Optoelectronic Properties of GaS Nanosheets Devices

Here, we report on using chemical vapor deposition to generate three kinds of gallium sulfide nanosheets, with thicknesses of approximately 10, 40, and 170 nm. Next, we performed Raman imaging analysis on these nanosheets to evaluate their properties. The 10 nm GaS nanosheets exhibited a nearly equal distribution of Raman imaging intensity, whereas the 40 and 170 nm GaS nanosheets exhibited an inclination toward the edges with higher Raman intensity. When the polarization of the laser was changed, the intensity of Raman imaging of the 10 nm thick GaS nanosheets remained consistent when illuminated with a 532 nm laser. Notably, a greater Raman intensity was discernible at the edges of the 40 and 170 nm GaS nanosheets. Three distinct GaS nanosheet devices with different film thicknesses were fabricated, and their photocurrents were recorded. The devices were exposed to light of 455 nm wavelength. The GaS nanosheet devices with film thicknesses of 40 and 170 nm exhibited a positive photoresponse even though the photocurrents were fairly low. In contrast, the GaS nanosheet device with a film thickness of 10 nm had a considerable current without light, even though it had a weak reaction to light. This study reveals the different spatial patterns of Raman imaging with GaS thickness, the wavelength of excitation light, and polarization. Remarkably, the I-V diagram revealed a higher dark-field current of 800 nA in the device with a GaS nanosheet thickness of approximately 10 nm, when using a voltage of 1.5 V and a laser of 445 nm wavelength. These findings are comparable with those theretical pretictions in the existing literature. In conclusion, the observation above could serve as a catalyst for future exploration into photocatalysis, electrochemical hydrogen production through water splitting, energy storage, nonlinear optics, gas sensing, and ultraviolet selective photodetectors of GaS nanosheet-based photodetectors.

Anticorrosion performance of nicotinic acid and nicotinic acid hydrazide blended with optimized potassium iodide against Q235 steel corrosion in acid-chloride medium

The most sorted corrosion-inhibiting additives are composed of compounds that are non-toxic, cheap, and soluble in an aqueous medium without requiring organic solvents or surfactants. Nicotinic acid (NTAD) and nicotinic acid hydrazide (NADH) are naturally derived compounds that are non-toxic, cheap, and very soluble in aqueous media. Hence, the present study investigates their anticorrosion performances in an equal mixture of 0.25 M H2SO4 and 0.5 M NaCl medium which mimics the acidic-chloride medium often encountered in typical industrial descaling and pickling processes. The study considered both the individual compounds and their blend with KI at different concentrations. The anticorrosion as well as the synergistic effects were evaluated with combined electrochemical and gravimetric methods. The low inhibition efficiency (%) approaching 50% and 70% were achieved with the individual NTAD and NADH, respectively, while enhanced inhibition efficiencies reaching 96% and 97% respectively, were achieved when blended respective inhibitors with an optimal KI concentration. The adsorption of the inhibitor molecules followed Langmuir isotherm with the Kads and ΔG0 increasing with the addition of KI. The positive synergistic index values confirmed synergism. The overall anticorrosion process as well as the synergistic effect of KI were validated with complementing intensive spectroscopy (FTIR and XPS analysis) and imaging (SEM and AFFM) methods. The experimental data collaborated with DFT computational and Monte Carlo molecular dynamics simulation studies in divulging the inhibition mechanisms of NTAD and NADH without and with KI blending.